This article explains how to set up a two-node load balancer in an active/passive configuration with HAProxy and keepalived on Debian Etch. The load balancer sits between the user and two (or more) backend Apache web servers that hold the same content. Not only does the load balancer distribute the requests to the two backend Apache servers, it also checks the health of the backend servers. If one of them is down, all requests will automatically be redirected to the remaining backend server. In addition to that, the two load balancer nodes monitor each other using keepalived, and if the master fails, the slave becomes the master, which means the users will not notice any disruption of the service. HAProxy is session-aware, which means you can use it with any web application that makes use of sessions (such as forums, shopping carts, etc.).

Imagine you have a machine with all of its disk full and another with unused gigabytes, and you do not want to move the data from one to the other. Why not use the second's disk on the first, you could do it with iSCSI, but you can do it with ATA over Ethernet (AoE) as well. It is the second method I will explain in this article. All of this was made with two computers running Debian Etch. http://www.howtoforge.com/ata_over_ethernet_debian_etch